Well drilling system



Aug. 29, 1933. w, TAYLOR 1,925,012

WELL DRILLING sYs'r'El Filed. Aug. 16. 19:32

Inventor:

William G Tc loh.

:25 motor becomes greater than a predetermined Patented Aug. 29, 1933UNITED STATES WELL DRILLING SYSTEM William G. Taylor, Schenectady, N.Y., aalignor to General Electric Company, a corporation of New YorkApplication August 1:, 1932. Serial No. czaoos 3Claims.

My invention relates to well drilling apparatus, more particularly to acontrol system for oil well drilling apparatus, and has for its object asimple and reliable system for controlling the pres- 5 sure of the drillon the earth's formation in response to the load on the main drivingmotor for the drill, together with means for maintaining normally apredetermined constant pressure of the drill on the earths formation.

My invention is more particularly an improvement on oil well drillingsystems wherein the drill is automatically fed so as to maintain apredetermined weight of the drill, i. e., pressure of the drill, on theearths formation, such as described 16 and claimed in the Loomis PatentNo. 1,779,480,

dated October 28, 1930.

In carrying out my invention, I control the feeding of the drill inaccordance with the suspended weight on the drill string in such amanner as to maintain a predetermined constant weight of the drill onthe earth's formation and I also provide means for retrieving the drillstring irrespective of the other conditions of operation in the eventthat the load on the main driving amount. For a more completeunderstanding of my invention, reference should be had to the accom- P 88 drawing the single figure of which shows in diagrammatic form a welldrilling system embodying my invention.

Referring to the drawing, I have shown my invention in one form asapplied to a well drilling system of the type adapted to feed the drillto maintain a predetermined substantially constant v pressure of thedrill on the earths formation such as described and claimed in theaforesaid Loomis patent. As shown the drill string 10 of the rotary typeprovided with a bit 11 is suitably suspended from a derrick by blocksand tackle (not fully shown) comprising a cable 12 passing through theblocks and having its ends secured respectively to the winding drums 13and 14. The winding drum 14, it will be understood, is provided withsuitable driving means (not shown) .whereby it may be'rotated to raisethe drill string out of the well. Duringnormai drilling operations,however, the drum 14 is secured against rotation and acts as a dead endfor that end of the cable. The drill is rotated by means of a suitableelectric driving motor 15, shown as of the three phase type, which isconnected through a suitable chain drive 16 and rotary driving mechanism17 to the drill 10. The driving mechanism 17, for example, may consistof bevel gears of suitable ratio.

As described and claimed in the aforesaid Loomis patent, the-drum 13 iscontrolled to gradually lower the drill string as the hole is ,60 bored.As shown, the drum can be rotated in either, direction by means of anelectric driving motor 20 which is connected to the drum through asuitable reduction gearing 21, a worm 22, a

.worm gear 23 and a chain andsprocket drive 24.

The worm 22 is suitably mounted for endwise movement, i. e., in thedirection of its axis of rotation, in response to the weight of thedrill string which is applied to the worm, it will be ob-= served,through the driving connections with the drum l3.

This endwise movement of the worm 22 which, it will be observed, isresponsive to the weight of the drill suspended on the cable 12, isutilized to control the electric motor 20 and thereby control thefeeding of the drill. To accomplish this the endwise movement of theworm is utilized to actuate an electrical contact arm 25 which ismovable between spaced adjustable upper and lower contacts to controlthe opening and closing of reversing switches 26 and 27 in the motorcircuit so as to control the starting and stopping of the motor and itsdirection of rotation. As shown, the end 0! the worm bears against aflexible diaphragm 28 forming a wallof a sealed fluid systemrincluding apipe 29 and a second flexible diaphragm 30. This movement of the worm inan endwise direction is thus transmitted and applied, at the pointdesired, to the diaphragm 30. The diaphragm 30 is in turn connected by arod 31 to a pivoted arm 32, the movable end of which is connected by alink to an operating arm 33 secured to the switch arm 25. Preferably,the switch arm 25 and the arm 32 are mounted in a sealed casing 34 whichcommunicates through a duct loosely surrounding the rod 31 with a casingenclosing the outer or right-hand side of the diaphragm 30. By means ofa suitable air pump 35 the air pressure can be varied in the chamber 34and on the right-hand'side of diaphragm 30,

as indicated by the pressure indicator 36, to adjust the response of thearm 25 to the tension in the cable 12. This arrangement of the pressureresponsive control for the switching means forms we no part of mypresent invention, however, it being described and claimed in acopending application of Caius E. Weaver, Serial No. 612,012, iiled May18, 1932, and assignedto the same assignee as this invention. no

I have also provided a relay switch 40 which is operated in response tothe load on the electric driving motor 15 so as to cause the motor 20 toretrieve or raise the drill in case the torque exerted on the drill, andtherefore the load on the motor 15, becomes too great. As shown, thisswitch comprises an electrically conducting bridging member 41 adaptedto be moved to bridge the upper contacts 42 or the lower contacts 43.The bridging member is operated by a coil 44 which is energized from asuitable current transformer 45 connected in one of the supply lines ofthe motor 15. When the load on the motor and the current in the motorcircuit is less than a predetermined maximum the current supplied to thecoil 44 is not great enough to lift the bridging member and consequentlyit remains in its lowermost position,

as shown, bridging the contacts 43. Upon an increase in motor load, andhence current, above the predetermined maximum, the bridging member islifted to bridge the upper contacts 42.

The relay'40 controls a switch comprising a bridging member 46 which maybe moved from one position to another to bridge the contacts 4'? or 48.This bridging member 46 is operated by means of two coils 49 and 50, thecoil 49 moving it to the position shown in the drawing to bridge thecontacts 47 while the coil 50 moves it to its opposite position tobridge the contact 48. The circuit to the coils 49 and 50 is controlledby the relay switch 40 and is further controlled by a pivoted contactarm 51 connected to the, common armature member 52 of the coils 49-50 soas to be moved to engage either the contact 53 or the contact 54. In theposition shown in the drawing the, arm 51 is in engagement with thecontact 53 and consequently when the bridging member 41 is moved toengage the contacts 42, a circuit will be closed from the supply main55- through the conductor 56, the bridging member 41, coil 50, thecontact arm 51 to the conductor 57. This energizes the coil 50 whichmoves the bridging member 46 in engagement with the contacts 48, andalso moves the contact arm 51 into engagement with the contact 54. Thismovement of contact arm 51 away from contact 53 opens the energizingcircuit of coil 50. Thereupon when the bridging member 41 drops to theposition shown, a circuit is closed for the coil 49 through the contactarm 51 whereby bridging member 46 is moved back to the position shown inthe drawing.

The position of the bridging member 46 determines whether the motor 20shall be controlled by the contact arm 25, or whether the motor 20 shallbe energized in a direction to raise the drill independently of theposition of the contact arm 25. In the position shown it will beobserved that the bridging member 46 is in the circuit of the operatingcoil 60 for the reversing switch 27 so that this coil as well as theoperating coil 61 for the reversing switch 26 can be controlled-by thecontact arm 25. With the contact arm25 in its uppermost position asshown, a circuit is closed from the conductor 56 through the conductor62, the contact arm 25 to the upper contact and thence through conductor63 and operating coil 61 to the supply main 57 whereby the coil 61 picksup the switch 26 and closes a circuit for the motor 20 in a direction toraise the drill. As the drill is raised its weight suspended .on thecable 12 increases thus moving the worm 22 towards the right as seen inthe drawing. Consequently the arm 32 and projection 33 arecorrespondingly moved towards the right and contact arm 25 is moveddownward. The motor continues to operate until the contact arm 25 movesto a position between its two contacts thus breaking the circuit for thecoil 61 whereupon the switch 26 is dropped open and the motor 20 isbrought to rest. When the weight of the drill string on the cablebecomes greater than the value for which the control is adjusted, thecontactarm 25 is forced downward into engagement with its lower contactwhereby a circuit is closed from the contact arm through the conductor65, the bridging contact 46, conductor 67, and coil 60 to the supplymain 5'7. This closes the switch 2'7 to start the motor 20 in oppositedirection to lower the drill whereby more weight is applied to theearths formation and the tension in the cable 20 is corerspondinglydecreased until finally the I contact arm 25 disengages its lowercontact to stop the motor.

In the event that the load on the motor 15, however, becomes'greaterthan a predetermined amount, the bridging member 41 of relay 40 israised to its uppermost position whereby the coil 50 is energized andthe bridging contact 46 is moved into engagement with the contacts 48.This closes a circuit from the conductor 56 through the conductor 68,the bridging contact 46, conductor 69, conductor 63 and the coil 61 tothe supply main 57 whereby the switch 26 is closed and the motor startedin a direction to raise the drill. This operation continues until theload on the driving motor 15 has been decreased to a predeterminedamount for which the relay 40 is set, when the relay drops down to theposition shown and the bridging member 46 is thereby moved back to theposition shown to deenergize the coil 61 and stop the motor. Thisretrieving action of the drill in response to the load on the motor 15,it will be observed, takes place entirely independently of the weightcontrol by the contact arm 25.

An alternative arrangement may be provided by removing or breaking asection 70 of the conductor 69 which section joins the upper contact ofswitch arm 25 to the junction of conductors 63 and 69. It will bereadily seen that this eliminates the retrieving action produced byexcessive pressure of the bit on the earth's formation which causesswitch arm 25 to be moved upward until it engages the upper contact, andwill therefore leave only the retrieving action produced by excessivetorque which increases the motor current, thereby causing relay 40 tomove bridging member 41 upward, as previously described. In other words,the equipment now feeds the drill downward in response to the weight ofthe drill, but retrieves the drill in response only to the torqueapplied to the drill as evidenced by the load on the motor.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1 The combination in well drilling apparatus, of a drill, hoisting meansfor raising and lowering the drill, an electric motor, a drivingconnection including a worm and a worm gear between said motor and saidhoisting means said worm being mounted for axial movement in response tothe suspended weight of the drill, control means for said motor, meansresponsive to movement of said worm for operating said control means tocause the motor to lower the drill when the pressure of the drill on theearth's formation becomes less than a predetermined value, a secondelectric mo or connected to rotate said drill and means responsive tothe current supplied to said second motor for operating said controlmeans to raise said drill in the event that the load on said secondmotor exceeds a predetermined value.

2. The combination in well drillir g apparatus of a drill, a drivingmotor for raising and lower-- ing said drill, means for controlling saidmotor for each direction of rotation, a control contact device movableto one position to close a raising circuit for said motor control meanswhereby said motor is caused to operate in a direction to raise thedrill and movable to another position to close a lowering circuit forsaid motor control means whereby the motor is caused to operate in adirection to lower the drill, means responsive to the suspended weightof the drill for controlling said contact device so as to cause saidmotor to lower said drill when the pressure of the drill on the earth'sformation becomes less than a predetermined amount, a second switchingdevice movable to one closed circuit position to close a portion of saidlowering circuit and to a second closed I circuit position to disablesaid lowering circuit 3. The combination in well drilling apparatus, ofa drill, a driving motor for raising and lowering said drill, means forcontrolling said motor for each direction of rotation, a control contactdevice movable to one position to close a circuit for said motor controlmeans to raise the drill and to another position to close a circuit forsaid motor control means to lower the drill, means responsive to thesuspended weight of the drill for controlling said contact device so asto cause said motor to lower said drill when the pressure of the drillon the earth's formation becomes less than a predetermined amount, asecond switching device movable to one closed circuit position to closea portion of said lowering circuit and to another closed circuitposition to disable said lowering circuit and complete said raisingcircuit independently of said contact device, separate windings formoving said second switching device respectively to said first andsecond position, means responsive to load current in said motor forclosing the circuit of one of said windings to operate said secondswitching device to said second position to raise said drill upon theoccurrence of a predetermined maximum load on said motor and for closingthe circuit of the other of said windings to return said secondswitching device to said first position upon the reestablishment of amotor load below said predetermined maximum, and means operated by saidsecond switching device for controlling the connections to saidwindings.

WILLIAM G. TAYLOR.

